a. Field of the Invention
This invention relates to improved methods of polymerizing acrylonitrile with certain acidic monomers.
B. Description of the Prior Art
The continuous aqueous slurry polymerization of acrylonitrile polymers is old and known. Typically, the polymerization conditions are adjusted to yield polymer at 65-75 percent conversion, with the unreacted monomers being separated from the polymer and recycled to the reactor. In the case of non-distillable, water soluble monomers or high boiling monomers this approach is often not feasible and the unreacted monomers are lost. Thus, it is desirable to maximize the incorporation of these monomers in the polymerization step.
The reactivity of the monomeric components in a polymerization reaction is governed by the reactivity ratios of the monomers. Unfavorable reactivity ratios can be compensated for to some extent by increasing the concentration of the monomer having the poorer reactivity ratio. However, this adds to the cost of the operation and results in even greater loss of unreacted monomer.